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Search: id:A112415
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| A112415 |
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C(1+n,1)*C(2+n,1)*C(4+n,2). |
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+0
2
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| 12, 60, 180, 420, 840, 1512, 2520, 3960, 5940, 8580, 12012, 16380, 21840, 28560, 36720, 46512, 58140, 71820, 87780, 106260, 127512, 151800, 179400, 210600, 245700, 285012, 328860, 377580, 431520
(list; graph; listen)
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OFFSET
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0,1
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FORMULA
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a(n)=(n+1)(n+2)(n+3)(n+4)/2=A033486(n+1)=12*A000332(n+4). O.g.f.: 12/(1-x)^5. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 15 2008]
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EXAMPLE
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If n=0 then C(1+0,1)*C(2+0,1)*C(4+0,2)= C(1,1)*C(2,1)*C(4,2)=1*2*6=12
if n=10 then C(1+10,1)*C(2+10,1)*C(4+10,2)= C(11,1)*C(12,1)*C(14,2)=11*12*91=12012
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MAPLE
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a:=n->add(binomial(n, 2)+add(binomial(n, 2), j=0..n), j=0..n):seq(a(n), n=2..30); [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 26 2008]
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CROSSREFS
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Adjacent sequences: A112412 A112413 A112414 this_sequence A112416 A112417 A112418
Sequence in context: A000141 A008530 A033486 this_sequence A061624 A004302 A000554
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KEYWORD
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easy,nonn
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AUTHOR
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Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 09 2005
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